What happened
On 18 November 2023, a training flight was underway near Brits Airfield (FABS) in the North West province. The flight, conducted under visual meteorological conditions, involved an instructor and a student pilot operating a Twin Astir glider, registration ZS-GPD.
The flight began with the glider in tow behind a tug aircraft, which lined up on Runway 20. Shortly after takeoff, while the aircraft were approximately 150 feet above ground level, the tug aircraft encountered a sudden downdraft. This atmospheric disturbance caused the tug to lose altitude rapidly, leading to a misalignment between the glider and the towing aircraft.
Because the tug was unable to maintain sufficient height, and noting that the standard release altitude is 450 feet, the crew initiated a left turn to return to the departure runway. Due to the lack of available thermals to sustain flight, the instructor pilot requested the release of the glider. The glider subsequently performed a forced landing in an open field. The impact caused the undercarriage to collapse and resulted in substantial damage to the tail boom. There were no injuries to the two occupants.
The investigation
SACAA AIID examined the circumstances surrounding the flight and the aircraft's maintenance status. The investigation confirmed that the instructor pilot held a valid Glider Pilot Licence and a current medical certificate. The Twin Astir was properly documented with a valid Authority to Fly and a Certificate of Registration.
Regarding maintenance, the aircraft's last annual inspection had been completed in February 2023. At the time of the accident, the airframe had logged 671.25 total hours, meaning only 14.67 hours had elapsed since the most recent annual inspection. No defects were noted in the flight records prior to the occurrence.